(a) Field of the Invention
The present invention relates to an arithmetic circuit, and more particularly to an arithmetic circuit having a function for transferring a carry or a borrow and adapted for use in an arithmetic and logic unit.
(b) Description of the Related Art
When a computation for binary operands of more than two bits is to be performed, a plurality of adding or subtracting circuits are used for the computation. With a plurality of adding or subtracting circuits (referred to as a arithmetic circuits hereinafter), a dynamic transmission circuit is generally used for transmitting a carry signal or borrow signal from a lower order position circuit to an adjacent higher order position circuit.
As for the arithmetic circuit having a dynamic transmission circuit, there is an advantage in which the configuration of the arithmetic circuit is much more simple than that of an arithmetic circuit of another type having a static circuit, and hence can operate in a higher speed. However, the dynamic transmission circuit has a drawback in which it is susceptible to noise, since the dynamic transmission circuit holds a data by storing electric charge across a parasitic capacitance thereof. The noise affecting the operation of the dynamic transmission circuit includes among others a noise caused by a cross-talk between the dynamic transmission circuit and other signal lines.